The prior art has seen a wide variety of approaches to forming automatically adjustable pipe wrenches. The closest art of which I am aware is U.S. Pat. No. 4,144,779 which shows that nut adjusted pipe wrenches are old. That patent then describes a way of employing an old style pipe wrench with rack-like teeth on the back of the stem in combination with a groove and a tiltable rocking-sleeve mechanism for automatically positioning the jaw.
A search of the prior art also reveals additional pertinent patents ranging from U.S. Pat. No. 864,155 which shows laterally movable dogs that move responsive to an engageable lateral member that can be broken by thumbs or the like to allow the dogs to be released, through U.S. Pat. No. 1,445,551 which shows a wrench that has rack-like teeth on the front of a handle that are engaged by dog-teeth on movable jaw. In between are similar patents; such as, a monkey wrench described in U.S. Pat. No. 994,070 in which teeth on a movable jaw are pivoted out of and into engagement with teeth on the handle; and U.S. Pat. No. 1,027,203 in which teeth on a movable jaw are pivoted by depression of push-button into and out of engagement with teeth on a handle. U.S. Pat. No. 1,181,380, 1916, describes biased teeth that are pivotally mounted to a movable jaw and can be clamped into engagement with teeth on a handle by hands or the like. U.S. Pat. No. 1,199,806 describes teeth on a movable jaw or the like. U.S. Pat. No. 1,199,806 describes teeth on a movable jaw that can be moved into or out of engagement with teeth on a handle. U.S. Pat. No. 1,336,460 describes a means of moving teeth on a movable jaw into engagement with teeth on a handle or the like, as does U.S. Pat. No. 1,064,361, the latter employing pivotally mounted biased teeth for large or fine engagement with teeth on the handle.
Thus the prior art shows that the principles are old in this crowded art; but the art has failed to provide a modern type pipe wrench in which the upper jaw is movable through a sleeve and has a slider block for clamping the stem along its side to retain an attained position, or fit; and that can be retrofitted onto existing pipe wrenches.